Here's What Happens To Your Dog's Brain When He Sees You

Dog has been man’s best friend for more than 18,000 years, and a new study has shown there’s a lot more evidence of our kinship with dogs than the look they give you when you come in from work.

Researchers from the University of Mexico have conducted MRI scans on dogs to delve into their emotional response when they come into contact with humans. Their findings were recently published in PLOS One.

The study rounded up five border collies, one golden retriever, and one labrador retriever from local families. After training the dogs to be comfortable and unrestrained in the MRI scanner, they were shown 50 images of different humans along with 50 images of inanimate objects.

A selection of the dogs used in the study, training to be comfortable in the MRI scanner University of Mexico/PLOS One

Their results showed that the dog’s temporal cortex lit up with activity when they were subjected to images of human faces. The temporal cortex is a part of the brain unique to mammals, involved in the high-level visual processing of complex stimuli, such as faces. The researchers "suggest that this portion of the temporal cortex in dogs could be anatomically and functionally similar to regions found in other species, like humans." This means dogs use a similar visual pathway as humans for processing faces.

When shown the images of humans, they also found a burst of activity in subcortical structures, such as the caudate. When shown the everyday objects, however, the caudate region showed distinctively less activity. The researchers said they believe this pocket of the brain is involved in reward processes, suggesting that dogs find seeing a human face “intrinsically more rewarding than the sight of an object.”

The findings strongly suggest that dogs have a keen ability to recognise human faces and emotional cues. Not just that, but the sight of a human really gets dog’s reward system ticking.

"In this case, they presented facial expressions and worked out that basically the same areas of the brain triggered in dogs as it does in humans in terms of reading and understanding facial cues," said Bradley Smith, an animal behaviourist from the Central Queensland University, commenting on the research to ABC Australia.

Through these findings, they also pondered the evolutionary history of this ability. Since previous studies have shown similar instances with non-human primates, sheep and humans, the researchers said it suggests this ability emerged early in the evolution of mammals before they branched off into their many orders and families.